Silicone release coatings are useful in applications where relatively non-adhesive surfaces are required. Single sided liners, such as backing papers for pressure sensitive adhesive labels, are usually adapted to temporarily retain the labels without affecting the adhesive properties of the labels. Double sided liners, such as interleaving papers for double sided and transfer tapes, are utilized to ensure the protection and desired unwind characteristics of a double sided self-adhesive tape or adhesive film.
Substrates such as single sided liners are coated by applying silicone release coating compositions onto the substrate, and subsequently curing the composition by thermally initiated hydrosilylation.
The basic constituents of silicone release coating compositions which are cured by hydrosilylation are:                (i) an alkenylated polydiorganosiloxane which can be a linear polymer or a branched polymer containing terminal and/or pendant alkenyl groups, most typically a linear polymer containing terminal alkenyl groups,        (ii) a polyorganohydrogensiloxane cross-linking agent designed to cross-link the alkenylated polydiorganosiloxane, and        (iii) a catalyst to catalyze the cross-linking reaction.        
Often a fourth constituent comprising an inhibitor (iv) is also included in the composition which is designed to prevent the commencement of curing below a prerequisite cure temperature. Silicone release coating compositions consisting of the three essential constituents (i)-(iii) and optionally the inhibitor (iv), are generally referred to as premium silicone release coating compositions.
In order to control the level of release force from such silicone release coatings, it has become common practice in the art for silicone release coating compositions to contain another additive known as a release modifier. The release modifier typically replaces a proportion of the alkenylated polydiorganosiloxane (i) in premium silicone release coating compositions.
Improvements in the performance of silicone release coatings are continuously being sought with respect to properties such as ease of cure, i.e. the decrease in cure times at relatively low temperatures, anchorage of coatings to substrates, and release performance. One factor which particularly necessitates continued development of such silicone release coatings is the use of an ever increasing number of substrates such as paper, polycoated kraft paper, polypropylene, polyethylene, and polyester, onto which such silicone release coating compositions are applied and cured.